The present invention relates to a badminton racket frame made of carbon fiber reinforced plastics or fiber reinforced plastics, especially to a badminton racket frame which is constructed seamless.
The known method for producing badminton racket frames comprises the processes of producing different parts such as a ring frame, throat, shaft and grip, and of constructing them into a whole racket. It is always difficult and complex to construct the above mentioned parts, especially the part between the ring frame and the throat. And the racket is easy to be broken at the throat when someone uses it to hit or smash a shuttlecock whereby causing accidents during the game.
The carbon fiber reinforced plastics (CFRP) or fiber reinforced plastics (FRP) has the advantages of high strength, good elasticity, high rigidity, good moisture-resistance, light weight, and good resistance to shock, damages, high temperature, and corrosion. Due to the above-mentioned advantages, the CFRP or FRP is used for manufacturing rackets of tennis, squash, badminton and the like.
The known racket frames, such as tennis racket frames, have been made of CFRP or FRP material to utilize the advantages of said materials especially for their good strength, elasticity, rigidity, moisture-resistance, creep-resistance and shock-attenuation.
A conventional method for producing racket frames adopts a mould which can form the frame, throat, shaft, and grip of the racket integrally by a single operation, a rubber tube filled with high-pressured gas is used there as the core of the mould. The CFRP or FRP prepreg material in the tube shape is placed in the mould and becomes hard by hot-pressing. The rubber tube is then pulled out from the mould and a kind of liquid foam plastic is poured into the core of the mould. Although this is a rather precise method, the compelex manufacture processes have caused this method to be discarded.
Another conventional method for producing the CFRP or FRP racket frames comprises a first process to insert the prepreg material in the mould and then a plastics film pipe filled with foaming material is arranged as the core of the mould. The whole racket frame can be hot-pressing moulded integrally by a single operation. This method is very popular in recent days. However, it still has some disadvantages. A plurality of plastics film layers are provided between the CFRP of FRP layer and the foaming material core, therefore the whole racket frame is not a single body. The foaming material core breaks from time to time by the force applied thereto whereby causing the center of gravity of the racket to deviate from its normal position and causing an unpleasant noise. Although this method is simple and the cost is low, the quality of the racket products is unfortunately decreased.
None of the conventional methods can produce a racket frame especially a badminton racket frame with a shaft having a diameter of about one millimeter.